Hiding Transmission Projects
Sep 6, 2006 - Ken Silverstein EnergyBiz
When Connecticut-based United Illuminating
wanted to build a 69-mile transmission line and place
24 miles of it underground, the idea got a warm reception
from the citizens of the affected communities. All
in all, the price tag in this case would not be any
higher than doing it all above ground because of rights-of-way
issues. But despite the good PR, no one likes to have
their neighborhoods dug up.
Without a doubt, an underground electrical infrastructure
is aesthetically more appealing. And, during periods
of extreme weather conditions, it has proven to be
more reliable. But going underground is an expensive
proposition. The Connecticut case withstanding, the
direct costs are much higher than those associated
with traditional overhead power lines. Meantime, it
is much more difficult to find trouble spots -- and
more time-consuming to fix them. The trend, though,
is toward placing electrical lines underground and
particularly in new communities that are under development.
"On the face of it, undergrounding is the way everyone
wants to go," says Kate Shanley, who handles public
outreach for United Illuminating. "Cost is a nebulous
issue until you get into the nuts and bolts."
Undergrounding has been driven by the inability
to accommodate overhead construction, she adds. The
Middletown-Norwalk project won't be completed until
2009 in part because of the complexity surrounding
the permitting process. For example, the cable must
make a river crossing and it appears that the utility
will be forced to build a bridge to do that. "People
like underground better than overhead but they like
it better in someone else's neighborhood," says Shanley.
The Edison Electric Institute funded a study on
underground transmission lines in 2004. The report
concluded that such technologies cost about 10 times
that of overhead power lines. And while underground
lines suffer a third of the outages as overhead ones,
they take twice as long to repair. Specifically, undergrounding
is about $1 million a mile. And the obvious question
is who will pay the price of installing that infrastructure?
The utility sector, by-and-large, says it is willing
to ante up at least the amount of what it would cost
them to go above ground. In fact, it says that about
half of the money it has spent constructing transmission
lines in the last decade has gone toward undergrounding.
One of the major costs involved with burying power
lines is the need to dig trenches. If, however, there
is new residential or commercial construction, the
effort could accommodate other utilities such as phone
and cable companies. The costs could then be shared.
The cost is oftentimes split among customers, developers
and utilities. In the end, though, it is consumers
who ultimately pay through higher taxes or higher
Lines above the ground come into contact with trees,
high winds, rain and ice storms. But, such wires are
much easier to repair because they can be visually
inspected whereas underground lines require special
equipment and crews to locate a fault and to fix.
That takes more time and money. At the same time,
water can seep underground, and particularly after
heavy flooding, that can cause systems to break down.
Florida Power and Light had been resistant to building
underground power lines or converting existing overhead
lines to underground ones. It said that the price
tag was "exorbitant" and that the process to do so
was too invasive. In fact, a March 2005 report by
the state's public service commission staff estimated
undergrounding the entire state could cost up to $94
billion -- raising electric rates by 81 percent for
But, the utility has changed its thinking because
of zoning laws in combination with having to endure
its fair share of hurricanes. Altogether, about 37
percent of its 71,000 miles of distribution lines
are buried underground. Of note, 84 percent of its
lines built in newly constructed communities use underground
power lines. Going forward, FPL adds that it will
pay a quarter of the cost to convert overhead lines
underground while supporting municipalities' efforts
to win state and federal funding for future endeavors.
The highest expenses are tied to excavation, installation
and service connection. In some cases, customers in
areas with underground wires will agree to pay extra
to cover the costs of construction. Dominion Virginia
Power, for instance, is required to collect one dollar
a month from residential customers and no more than
$5 a month from business customers. The money is escrowed
and used to covert overhead power lines to underground.
"Underground distribution lines will improve the
potential for reduced outage interruption during normal
weather, and limit the extent of damage to the electrical
distribution system from severe weather-related storms,"
says Duke Power, in the institute's report. "However,
once an interruption has occurred, underground outages
normally take significantly longer to repair than
a similar overhead outage."
But there are other variables that businesses and
communities take into consideration: reduced motor
vehicle accidents, less economic harm as a result
of fewer outages and increased property values. And
utilities enjoy other advantages, too: fewer greenhouse
gas emissions are released, the efficiency of the
system is increased and trees do not need to be trimmed
to avoid power lines -- all because of undergrounding.
The technologies to build underground lines are
also getting better and cheaper. Horizontal directional
drilling allows conduits to be placed underground
without opening trenches. Similarly, high-voltage
insulated underground cables are proving to be more
durable while cable trenches located in sidewalks
and covered by "pavers" are supposedly easy to remove
and allow for simple maintenance.
Some utilities are embracing the potential trend.
Pacific Gas & Electric just installed two underground
systems. The first is a 230 kilovolt transmission
line at a cost of $221 million. All but three miles
of the 27-mile Jefferson-Martin are underground. The
second -- the Potrero-Hunters Point Cable -- is a
115 kilovolt transmission line that cost $40 million
and spans 2.5 miles.
Meanwhile, ComEd plans to make a $190 million investment
to increase the electric power supply to the northern
portion of the central business district, where consumption
continues to grow. The 345 kilovolt, 12-mile line
will be mostly underground. "Our customers depend
on electricity for their quality of life, and they
expect us to operate, maintain and invest in a reliable
electricity delivery system to keep up with the economic
growth of Chicago," says Fidel Marquez, ComEd's vice
president-external affairs for Chicago operations.
Clearly, it's difficult to make an economic case
for building underground transmission lines. But,
communities are interested in the idea and particularly
customers who will live in newly developed areas where
costs can be shared among various utilities. Indeed,
the aesthetical value along with the possibility of
avoiding widespread blackouts has gained credence
in the utility world. The stumbling block, though,
remains over the issue of who will pay for the advances.
And that still clouds the future of undergrounding.